// Copyright 2021 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package snippets

// [START compute_usage_report_set]
import (
	"context"
	"fmt"
	"io"

	compute "cloud.google.com/go/compute/apiv1"
	computepb "google.golang.org/genproto/googleapis/cloud/compute/v1"
	"google.golang.org/protobuf/proto"
)

// setUsageExportBucket sets the Compute Engine usage export bucket for the Cloud project. This sample presents how to interpret the default value for the report name prefix parameter.
func setUsageExportBucket(w io.Writer, projectID, bucketName, reportNamePrefix string) error {
	// projectID := "your_project_id"
	// bucketName := "your_bucket_name"
	// reportNamePrefix := ""
	ctx := context.Background()
	projectsClient, err := compute.NewProjectsRESTClient(ctx)
	if err != nil {
		return fmt.Errorf("NewProjectsRESTClient: %v", err)
	}
	defer projectsClient.Close()

	// Updating the setting with an empty UsageExportLocationResource value disables the usage report generation.
	req := &computepb.SetUsageExportBucketProjectRequest{
		Project: projectID,
		UsageExportLocationResource: &computepb.UsageExportLocation{
			BucketName:       proto.String(bucketName),
			ReportNamePrefix: proto.String(reportNamePrefix),
		},
	}

	if reportNamePrefix == "" {
		// Sending an empty value for reportNamePrefix results in the next usage report being generated with the default prefix value "usage_gce". (see: https://cloud.google.com/compute/docs/reference/rest/v1/projects/get)
		fmt.Fprintf(w, "Setting reportNamePrefix to empty value causes the report to have the default prefix value `usage_gce`.\n")
	}

	op, err := projectsClient.SetUsageExportBucket(ctx, req)
	if err != nil {
		return fmt.Errorf("unable to set usage export bucket %v", err)
	}

	globalOperationsClient, err := compute.NewGlobalOperationsRESTClient(ctx)
	if err != nil {
		return fmt.Errorf("NewZoneOperationsRESTClient: %v", err)
	}
	defer globalOperationsClient.Close()

	for {
		waitReq := &computepb.WaitGlobalOperationRequest{
			Operation: op.Proto().GetName(),
			Project:   projectID,
		}
		op, err = globalOperationsClient.Wait(ctx, waitReq)
		if err != nil {
			return fmt.Errorf("unable to wait for the operation: %v", err)
		}

		if op.Proto().GetStatus() == computepb.Operation_DONE {
			fmt.Fprintf(w, "Usage export bucket has been set\n")
			break
		}
	}

	return nil
}

// [END compute_usage_report_set]
